SEOUL (Reuters) - Kim Hae-sook was only 13 years old when she was dragged off to a North Korea prison camp for nearly 30 years, punished along with the rest of her family simply because her grandfather fled to rival South Korea in the 1960s.
For most of that time, she was put to work in one of the state's notoriously dangerous mines, working 16-18 hours a day.
Thousands of people are believed to be held as "guilty-by-association" or sent to the North's labor camps simply because one of their relatives has been detained, Amnesty International said in a report this week.
By the time Kim was released from the "Bongchang-ri Camp No. 18" some 28 years later in 2002, having scavenged on grass to survive, three of her family had either starved to death or were killed in accidents.
Emotionally, Kim was left scarred for life and is haunted by her family's suffering and the horrific scenes of torture and executions at the camp in Bookchang, South Pyongan Province, north of the capital Pyongyang.
"I have seen public executions hundreds of times," Kim now 50 and out of North Korea, told Reuters in a telephone interview on Wednesday.
"A lot of people were executed by firing squad. If someone believes in a superstition, then that person would be hanged," she said.
Kim's first few years in the camp were spent scrounging for food, picking grass and herbs to supplement her family's meager diet of corn.
"They gave us only what we needed not to starve to death," she said. "I just endured it, picking up leaves to eat. I knew that if I didn't I would die from starvation.
"If they told us to die, we did. If they wanted to beat us, we let them," she added.
At the age of 16, all the detainees were sent to work in the mine, Kim says. Her brother, like thousands of others, died while working in the pit.
When Hae-sook was finally released in 2002, for good behavior, she says the camp housed about 17,000 people.
The Amnesty report said the isolated state, under international sanctions for developing nuclear weapons and condemned for its human rights record, now holds about 200,000 people in their huge political prison camps.
It said satellite images showed that the size of six camps in South Pyongan, South Hamkyung and North Hamkyung provinces, which are believed to have been operating since the 1950s, had significantly increased in the past decade.
"We don't have concrete figures ... North Korea is never going to come up and say 'we do have this number of political prisoners'. Everything is based on guessing," said Kim Tae-jin, the president of Democracy Network against North Korean Gulag.
Kim, himself, was held at the Yodok camp for four years until 1992. "Once you step into the camp, your soul is deprived. You no longer think that you are alive even though you are alive."
Amnesty called on North Korea, one of the world's most secretive states, to close all political prison camps and to release all prisoners of conscience.
"North Korea can no longer deny the undeniable. For decades the authorities have refused to admit to the existence of mass political prison camps," Sam Zarifi, Amnesty International's Asia Pacific director, said in a statement.
"As North Korea seems to be moving toward a new leader in Kim Jong-un and a period of political instability, the big worry is that the prison camps appear to be growing in size," he said, referring to the son and presumed successor of leader Kim Jong-il.
For Kim Hae-sook, her connection with Bongchang-ri Camp No. 18 remains as strong as ever.
Her siblings are still being held in detention over 40 years after they were first taken there from their home in the back of an army truck.
Additional reporting by Adrian Croft in LONDON; Editing by Robert Birsel